1. Field of the Invention
The present invention relates to a press arrangement of a paper or carton machine for the treatment of a fibrous pulp sheet in a press opening.
2. Background of the Invention
Typically, the press opening of a press arrangement extends in the run direction of the fibrous pulp sheet and is defined by two press surfaces. It is known to have at least one of the press surfaces constructed of a flexible press sleeve that is guided over a press shoe, such that a resulting main press force, acting in one direction, is exerted. The resulting main press force is directed essentially perpendicular to the fibrous pulp sheet that is being guided through the press opening.
In a press arrangement of this type, the pressure force profile that is established in the press opening and along the run direction of the fibro is determined by the given relative shape of the press shoe and the suitable hydraulic arrangements located on the opposing press surface.
It is generally known to exert an additional force on the press shoe with the aid of additional pistons on the entrance or exit side, i.e. outside the main target area. The additional pistons supply the press shoe with increased pressure force on the entrance or exit side, causing the pressure profile to tilt and causing a corresponding increase in pressure force.
It is possible to compensate for the effect of the additional forces by employing technical control measures for the main loading force. This process, however, is disadvantageous because it is associated with significant expense and risk respecting possible disturbances impairing the functional safety of the press arrangement. Thus, the productivity of the paper machine facility may be adversely affected.